This article in the Herald Mail Media states:

“the most important document people should be getting right now is the equivalent of a medical power-of-attorney. The document’s name depends on the state. . . . First, appoint an agent or decision-maker for healthcare decisions in case you are unable to make or communicate an informed choice yourself . . . . Second, the document should express your wishes in case you end up in a terminal condition or persistent vegetative state. Do you want interventions or not?”